.image {
    display: block;
    position: relative;

    &.is-48x48 {
        width: 48px;
        height: 48px;
    }

    &.is-128x128 {
        width: 128px;
        height: 128px;
    }

    & img {
        display: block;
        height: auto;
        width: 100%;
    }

    &.is-4by3 {
        /* 使高度为长度的75% */
        padding-top: 75%;

        & img {
            position: absolute;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
        }
    }
}

